1. Field of the Invention
The present invention relates to a clamping device for a ski boot with a rotatably mounted wind-up element.
2. The Prior Art
A clamping device of this type is known, for example, from FR-A-2,561,878 or the corresponding U.S. Pat. No. 4,631,839. A winding-up element for the winding up and unwinding of a band-shaped clamping element and a transmission member equiaxial with this are releasably connected to one another by means of a gear wheel. The transmission member is fixedly guided in terms of rotation, but axially displaceably, in a cylinder body rotatably mounted at a fixed location. Using a take-up connection rotatable in the winding-up direction of the winding-up element, the cylinder body is connected to a bearing element which is rotatably mounted in a housing about the axis of the winding-up element and of the clamping element. A lever-shaped actuating element is arranged on the bearing element pivotably about a shaft extending at right angles to this axis and intersecting the latter. The cylinder body and therefore the transmission member are prevented from rotating oppositely to the winding-up direction by means of a return catch device. A spring presses the transmission member in the opening direction of the coupling against the actuating element which is designed in the form of an eccentric on its periphery in the region of the shaft. For winding up the clamping element, the actuating element is pivoted through 90 degrees about the shaft out of its rest position, it bears against the housing of the clamping device, so that it extends approximately in the radial direction in relation to the axis of rotation of the transmission member and of the winding-up element. The coupling with the transmission member and the winding-up element is thus always kept closed, since the periphery of the actuating element is made cylindrical in the region corresponding to the shaft. Now the actuating element is pivoted to and fro within a working pivot range, with the result that the winding-up element is driven intermittently in the winding-up direction. If the clamping element has the desired tension, the actuating element is pivoted back into the rest position, and the coupling remains in engagement and therefore the tension in the clamping element is maintained. Now when the clamping device is to be released, the actuating element is pivoted out of the rest through 180 degrees about the shaft. The result is that the transmission member is displaceable in the direction of its axis of rotation under the force of the spring, since the distance between the periphery of the actuating element, against which the transmission member bears, and the shaft decreases during the second half of this pivoting movement. The coupling is thereby opened and the winding-up element is released for rotating in the unwinding direction. This known clamping device is complicated in terms of both its construction and its operation.
A further clamping device with a rotatably mounted winding-up element for the winding up and unwinding of a cable-shaped clamping element is known from FR-A-2,593,682 or the corresponding U.S. Pat. No. 4,719,670. There projects on one side from the drum-shaped winding-up element a shaft, on which an essentially hollow-cylindrical transmission member is located and is freely rotatable. This is prevented from rotating oppositely to the winding-up direction by means of a return catch device. In the region facing the winding-up element, the transmission member is made disk-shaped and has a recess into which a pin projecting from the winding-up element engages. On the side facing away from the winding-up element, the transmission member is likewise made disk-shaped and has a further recess. This interacts with a driving nose of a bearing part, on which an actuating element is arranged pivotably about an axis at right angles to the axis of rotation of the winding-up element and intersecting this. During the rotation of the actuating element in the winding-up direction, the transmission member is taken up by the driving nose and the winding-up element by the pin engaging in the recess of the transmission member. When the actuating element is moved oppositely to the winding-up direction, the transmission member and therefore the winding-up element are prevented from corotating in this direction by the return catch device, the driving nose coming out of engagement with the corresponding recess. To release the clamping device, the shaft and therefore the winding-up element are pressed downwards, for example by means of the ski pole, with the result that the pin comes out of engagement with the corresponding recess in the transmission member. The winding-up element is thereby released. A disadvantage of this clamping device is that a tool, for example the ski stick, is necessary for the release.
A further clamping device is known, for example, from U.S. Pat. No. 4,433,456. This has a drum-shaped winding-up element for the winding up and unwinding of two clamping cables, which is permanently connected operatively to a transmission member via a gear having teeth. The transmission member and therefore the winding-up element are releasably prevented from rotating oppositely to the winding-up direction by means of a disconnectable return catch device. Located as a nut on a thread on the transmission member is an actuating element which, during rotation in the winding-up direction, runs axially onto a take-up stop on the transmission member and drives the transmission member or the winding-up element in the winding-up direction. For unwinding the clamping cables, the actuating element is rotated oppositely to the winding-up direction, the latter moving away from the take-up stop in the axial direction of the transmission member and having a releasing effect on the return catch device. The transmission member and, therefore, the winding up element are thereby released for unwinding the clamping cables. Now a disadvantage of this known clamping device is that, in order to release the winding-up element so as to unwind the clamping cables, the actuating element has to be rotated through a large angle. It is necessary, furthermore, in order to unwind the clamping cables, for the actuating element to be corotated in the unwinding direction, otherwise the return catch device is activated again as a result of the rotation of the transmission member in relation to the actuating element and a further unwinding of the clamping cables is, thus, prevented.
A further clamping device is known from EP-A-0,255,869. This likewise has a drum-shaped winding-up element for the winding up and unwinding of clamping cables, which is permanently connected operatively to a transmission member via a Maltese-cross, toothed or planetary gear. A two-armed catch lever is pivotably mounted on the transmission member by means of one lever arm so as to be prestressed towards a catch toothing on the housing of the clamping device. The other lever arm engages into a control cam of an actuating element connected via a take-up connection which, during the change of the direction of rotation of the actuating element, allows an idling pivot angle of the actuating element in relation to the transmission member. During the rotation of the actuating element in the winding-up direction, the control cam releases the catch lever and the take-up connection takes up the transmission member and, therefore, the winding-up element in the winding-up direction. The catch lever engaging into the catch toothing prevents the transmission member and, therefore, the winding up element from rotating oppositely to the winding-up direction. For unwinding the clamping cables, the actuating element is rotated oppositely to the winding-up direction, with the result that the control cam now releases the catch lever from the catch toothing and the take-up connection takes up the transmission member and, therefore, the winding-up element in the unwinding direction. In this clamping device, admittedly a rotation of the actuating element through a smaller angle is necessary for releasing the catch lever. But for unwinding the clamping cables, the actuating element has to be corotated continuously in the unwinding direction, otherwise the control cam releases the catch lever again and, thus, prevents a further release of the clamping cables.